Siting Evaluations for Various Wind Projects

CLIENT: Navigant Consulting

IEC provided wind data acquisition and analysis, wind plant conceptual design, balance of plant conceptual design, and wind plant cost estimating for various proposed wind projects in California. For the wind data acquisition and analysis, IEC obtained information about the potential sites, including wind data, coordinates, location of existing facilities (buildings, transmission lines, etc.), topology (ridgelines, treelines, etc.), and similar features in the general vicinity. IEC also obtained wind data. Our experts then scrubbed (removed poor quality data) and analyzed this data to determine:

  • Wind speed and direction at different potential hub heights;
  • The change in wind speed with height – termed the wind shear;
  • The diurnal characteristics of the wind which help define the time-of-day energy deliveries of a wind turbine;
  • The joint frequency of wind speed and wind direction which assist in the engineering design of the wind turbine array; and
  • The wind turbulence at the site.

Based on the results of the above data and analyses, we analyzed the wind data in relation to wind power curves and other specifications for one of the most applicable wind turbine generator models currently available in the market. A preliminary siting for the turbine model was also performed, taking into account topological features and other constraints, to develop a total number of wind turbines and generating capacity expected. The annual capacity factor for the potential wind plant based on the wind turbine model was then estimated.

A preliminary sizing and routing of the electric collector system, substation/switchyards, and access roads was performed and a capital cost estimate was developed. Wind turbine generator prices were requested from the respective manufacturer, along with estimates of erection and commissioning costs, lead time and other terms and conditions. Balance of plant costs were also estimated including the cost of engineering, procurement and construction of the collector system, access roads, administrative and maintenance facilities, and other facilities. An estimate of “soft costs” was also developed, including permitting and compliance, interconnection studies, project management, legal and financing costs. Finally, annual O&M costs were estimated including labor, maintenance, property taxes and other costs.